


Brown Eyes

by SailorChibi



Category: Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Age Play, Bucky Barnes Feels, Bucky Barnes Has PTSD, Bucky Barnes Needs a Hug, Caregiver Bucky Barnes, Caregiver Steve Rogers, Dad Bucky Barnes, Dad Steve Rogers, Domestic Avengers, Father-Daughter Relationship, Hydra does a lot of creepy shit, Major Original Character(s), Multi, Not Avengers: Infinity War Part 1 (Movie) Compliant, Not Captain America: Civil War (Movie) Compliant, Other Winter Soldiers, Post-Avengers: Age of Ultron (Movie), Protective Steve Rogers, Team as Family, Tony Stark Feels, Tony Stark Has A Heart, Tony Stark Has Daddy Issues, age play is with the original character, bucky barnes has a daughter, caregiver tony stark, completely ignores any events after ultron, dad tony stark, non sexual age play, not wanda maximoff friendly, original character is a winter soldier, original character is bucky's daughter
Language: English
Status: Completed
Published: 2019-12-28
Updated: 2020-02-28
Packaged: 2021-02-25 23:40:43
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 7
Words: 14,496
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21993874
Author URL: https://archiveofourown.org/users/SailorChibi/pseuds/SailorChibi
Summary: Tony is used to being a man of the future, but he's not used to his discoveries rocking the very foundations of the avengers. But maybe this newest discovery might also be just the thing to pull him, Bucky and Steve fully together.
Relationships: James "Bucky" Barnes/Steve Rogers/Tony Stark
Comments: 61
Kudos: 459





	1. Chapter 1

**Author's Note:**

> This was a commission for someone who wanted age play involving her original character. I hope that you enjoy it!

"Sir, the results are in and are ready for your perusal."

Tony pried his eyes open and sighed as the ceiling of the workshop slowly swam into focus. Pushing himself up, he tiredly rubbed at his eyes and squinted around the room. JARVIS had dimmed the lights, but it was still bright enough for Tony to see that Dummy, Butterfingers and You were all in their docks. There was a now cold mug of coffee right beside Tony's ankle that definitely hadn't been there when he passed out however many hours ago. Tony smiled slightly. No doubt the coffee was a gift from Dummy. Too bad Tony didn't dare drink it.

"J, what time is it?" he asked, grimacing and rubbing at the nape of his neck. Pepper threatened to trash the couch in his workshop every time she came down here; so far Tony had managed to fob her off by claiming that the couch was incredibly comfortable, but maybe it was time to be honest. Either Tony was just plain old, or the days when the couch was capable of giving someone a good night's sleep had long-since passed. Or both. It was probably both.

"It's just after midnight. Captain Rogers requested that I pass along a message when you woke," JARVIS said.

"Oh did he," Tony said, amused. "And what did our good captain say?"

"That if you didn't show up to breakfast tomorrow morning, he was going to send Clint and Natasha down here to ferret you out," JARVIS replied, and Tony let out chuckle. Yup, that sounded like Steve.

"Guess that means I better get to it, huh?" Tony said, getting up. It was a bit of a relief when his legs didn't collapse out from under him, to be honest. He walked unsteadily to his desk and sat gladly in his chair, rolling his shoulders as JARVIS pulled up the holograms. 

The smile slowly faded from Tony's face as he took in the data that JARVIS had compiled. If it was right - and he was sure that it was - then this was bad. Really bad. Tony exhaled slowly and pulled the first page closer to him. He lost himself to several hours of examining the data and reading up on what JARVIS had found. When he was finished, he just sat there for a long time and stared at the top of his desk in thought. JARVIS knew enough to remain silent and instead began compiling the data, including a brief overview.

"You're being summoned for breakfast," JARVIS said a while later.

"Right. Breakfast," Tony muttered, closing his eyes. He rubbed his temples and sighed heavily. If he didn't go upstairs, then someone was going to come downstairs to get him. Whoever it was would probably immediately recognize that something was wrong. And this wasn't a conversation Tony wanted to have on an empty stomach.

He stood up and made his way out of the workshop, heading for the elevator. JARVIS obligingly took him up to the common floor. The doors opened to chaos; Tony narrowly avoided being hit in the head with a toy purple arrow. Clint called an apology over his shoulder as he sprinted by. Natasha was hot on his heels, murder written across her face. Bruce was sitting on the couch shaking his head, while Thor laughed and shouted encouragement to Natasha. In the kitchen, Tony could just make out the sight of Bucky and Steve standing at the counter finishing off breakfast.

His heart warmed. After Ultron, Tony hadn't really been sure if the team would pull themselves together or not. They'd come through by a very narrow margin. It had helped that Steve and Tony had finally sat down and had a very serious conversation. The information about Bucky had hurt more than Tony ever wanted to admit, and it had taken him a few weeks to accept the truth about his parents and the Winter Solider. But after some long talks with Rhodey and a few drinking sessions, he'd poured all of considerable resources into helping Steve find and bring Bucky Barnes home where he belonged.

Now, Tony was more grateful than ever that things had turned out the way they had. The Avengers were a pretty strong team, certain members like the Scarlet Witch notwithstanding, and he was almost positive that they were going to come through this latest bomb okay. Or at least, Tony hoped that was the case. At any rate, it wasn't like he could hide what he'd found. Sooner or later this was going to come out in the open and it was in everyone's best interest if the Avengers were able to get ahead of this particular shitshow.

Still, that made it no less easy to walk into the kitchen and accept Bucky's and Steve's greetings. Sam was sitting at the table, heckling Steve, and Tony joined him. He watched Bucky and Steve without speaking. They didn't seem to notice his attention, especially since the rest of the team more than made up for Tony's silence as they piled into the room. Bucky and Steve served a heaping pile of food for breakfast and they all dug in, Tony included. He ate hungrily, but as soon as the edge had been taken off, he set aside his fork. Naturally, Natasha noticed immediately.

"What's up, Antoshka?" she asked, not once pausing in the mock battle she was having with Thor. Their forks clashed together as they fought for the last dumpling.

"I found something," Tony said, very softly.

"Found what?" Natasha said, her smile fading. Thor turned to look too, and then one by one so did everyone else until Tony was the center of scrutiny. Normally that was a position he loved, just not today.

"Show them the picture, J," Tony said, pushing his plate away. He watched tiredly as they all looked at the holographic picture JARVIS was projecting onto the nearest wall. It showed a young woman somewhere in her late teens or early twenties - Tony was an excellent judge of age, so he was pegging her at about nineteen or twenty. She had dark brown hair and eyes and full, unsmiling lips. A small, thin nose, low cheekbones, arched eyebrows and a broad forehead combined to make her... not attractive, exactly, but someone who would be able to easily blend into a crowd as unremarkable.

He figured that was the whole point.

"I don't understand," Thor said. "Who are we looking at?"

Tony sighed. "As far as I can tell, her name is Katrianne," he said.

"Okay..." Clint said slowly. "Is that supposed to mean something?"

"It will. She's another Winter Solider," Tony said, keeping his eyes on Bucky. He could pinpoint the moment when his words landed. Bucky's smile just dropped. A whole range of emotion flashed across his face before settling onto an icy blankness that made Tony want to cringe.

“There are more Soldiers?” Sam said, setting his fork down to give the hologram his full attention.

“Apparently. I still have to do some digging to see if there are any more. This – she – is the only other one I’ve found so far,” Tony said. 

“Where is she?” Bruce said, asking the obvious question.

“In France, so far as I can tell,” Tony answered.

Thor nodded. “That would make sense. Strategically, they would not keep all of their Soldiers in one place.”

“But who _is_ she?” Natasha said, narrowing her eyes at the picture. 

Tony licked his lips. Here came the difficult part. “She wasn’t kidnapped, I don’t think, if that’s what you’re asking. Based on everything I’ve looked into, it seems that Hydra started experimenting with test tube babies. I guess it makes sense, considering they’re into every other heinous thing out there –”

“Tony,” Steve interrupted, and for the first time Tony looked over at him. Steve was very pale. His knuckles were white where he was gripping his fork. Tony was positive that later, when Steve let go, that poor fork was going to be twisted beyond recognition.

“I think… I think she’s Bucky’s daughter,” Tony said reluctantly.

There was a split second of complete silence, and then Bucky stood up. Without a word, he walked away from the table. Natasha and Sam both got up and went after them, leaving Tony at the table with Bruce, Steve, Clint and Thor. No one said anything. Tony, staring at his half-full plate, took a moment to be grateful at least Wanda was out of town with Vision. Her presence would’ve made everything worse.

“How?” Bruce said finally. “I - _how_?!”

“I don’t know. Maybe Hydra ordered the Winter Soldier to fuck some girl, who knows,” Tony said tiredly, running a hand through his hair. “Maybe they extracted semen from him somehow. The point is, we can get a paternity test done after we rescue her.”

“Rescue her?” said Clint. “Uh, just throwing this out there, but how do we know that she even wants to be rescued? Maybe she’s a good little Hydra agent.”

“I’ve found references to the chair in her files,” Tony said, but he couldn’t deny that Clint had a valid point. They didn’t know anything about her beyond what Tony had managed to find in the files, and it wasn’t like they had ever encountered another Soldier before. Bucky could’ve been a special case.

“It might be smart to do more research first,” Bruce said. “What did you –”

“No. We have to help her,” Steve said.

Thor, Bruce, Tony and Clint all exchanged a look. Tony suddenly had his regrets about bringing this up when Steve was around. He should’ve known better. When it came to Bucky, or anything relating to Bucky, it was like Steve lost all of his good sense and gained tunnel vision. He’d been getting better about it, but Tony had to wonder if this was going to bring about a relapse.

“Steve, you don’t know if she’s safe for anyone to be around,” Clint pointed out.

“Aye. It would be wiser for Tony to do more research,” Thor said.

Steve shook his head. “No. We – we’re going.” He got up and walked out without another word. Clint gave Tony an expectant look. Tony sighed and followed.

“No one is saying that we shouldn’t help her,” Tony said, trailing behind. “We’re just saying that we have to make sure it’s _safe_. You remember what Bucky was like. You were the only person who could get through to him and even that was almost impossible. This Soldier has no previous connection with any of us, Steve. She’s been with Hydra her whole life.”

“Then we have to find out,” Steve said, turning to face Tony. “You couldn’t have known that Bucky could be rescued just by what Hydra’s records said, right? They believe that all traces of Bucky Barnes were gone. I know it’s not the same situation, but… she could be Bucky’s _kid_.”

Tony sighed and crossed his arms, tapping his foot on the floor. It was so annoying when Steve was right. “Okay, fine. You have a point, and I have a location.”

“You do?” Steve said, surprised.

“It looks like she’s being kept at a secondary Hydra base. We could raid it… see what we find…” Tony shrugged. “If Bucky is okay with that.”

“Bucky…” Steve muttered, eyebrows furrowing.

“He looked pretty freaked out,” Tony said.

“We should go check on him,” Steve said, holding out a hand. Tony took it and they headed into the elevator.

Bucky had retreated to Steve’s floor, unsurprisingly. Natasha and Sam were talking to him, but they both got up and left when Tony and Steve came in. Tony took the meaningful look that Natasha sent him to heart, knowing that this was going to be a delicate subject. Bucky had made amazing progress since being officially pardoned for his crimes as the Winter Soldier, but he still had bad days and probably always would.

“Hey Buck,” Steve said cautiously. “You okay?”

“I’ve been better,” Bucky said with a bitter smile. “It’s really true, Tony?”

“There really is another Soldier. That’s all I can tell you for sure right now,” Tony replied quietly. It seemed likely that the Soldier was Bucky’s daughter, but they didn’t have concrete proof yet. He had no idea what they were going to do if that was the case. It would change _everything_.

“Then I guess we have to find out,” Bucky said determinedly, and Steve reached out his free hand to clap it on Bucky’s shoulder. Tony swallowed, nerves fluttering in his stomach, but nodded.

“I guess we’ll get the jet ready,” he said.


	2. Chapter 2

Tony sort of expected that something so earth-shattering would turn out to be difficult. But as it turned out, storming the Hydra base was, dare he say it, easy. Apparently, Hydra had never stopped to consider that someone might figure out they were keeping something valuable at a second-rate base, and their defences reflected that. The Avengers were in and out within three hours… and they took something with them.

“She really does look like Bucky,” Clint said, folding his arms over his chest.

“You think?” Bucky said. He stood next to the capsule, not smiling. Tony’s eyes flicked between the unconscious woman and Bucky and realized that Clint was right. There was a certain resemblance, though on the whole Bucky was a lot more attractive. Not that Tony was going to say that. He valued his life too much for that.

“She looks more like your younger sister than your daughter because of the age difference. I wonder who her mother is?” Bruce mused, more to himself than to the rest of them. He was already immersed in the documentation that JARVIS and Tony had nabbed, but since it was written in French, he was having to go through it slower.

“Probably someone who is no longer alive,” Natasha said from where she was piloting the plane. Sam, seated beside her, bowed his head.

Tony had to admit that she had a point, even though the realization made him feel slightly ill. Looking at the Soldier, he had to wonder if she’d ever even had a life. Had she known her mother? She certainly hadn’t known her father, so that seemed unlikely. Had Hydra kept her asleep for most of her childhood? Was this capsule where she’d grown up? Or had they instituted her into a Black Widow-like program, training her from a young age?

“We can look into it,” Tony said when the silence had dragged on uncomfortably long. “I have JARVIS doing a translation of that stuff, Bruce. That’ll help.”

“Good. I’m having a hard time understanding the local dialect they’re using,” Bruce said, sitting back and rubbing his face wearily.

“Let me try. I was stationed in France for a month once,” Clint said, walking over to join Bruce. 

Thor had remained behind with SHIELD to help them dismantle the base. Surprising everyone, Steve had also volunteered to stay behind. Tony wasn’t sure why. He would have thought that Steve would’ve wanted to be with Bucky, but maybe Steve needed the space. Maybe staying behind to bunch Hydra agents in the face was going to be excellent therapy for their resident captain. He snickered to himself at the thought.

“What’s so funny?” Bucky asked, stepping away from the capsule. 

“Just thinking to myself that Steve is probably giving those Hydra agents a _really_ bad day,” Tony told him. He reached out unconsciously, tucking a strand of hair behind Bucky’s ear; Bucky always tied his hair back during missions, but the slightly curly texture of his hair meant that pieces continuously escaped.

For the first time since Tony had opened his mouth at the breakfast table, Bucky smiled. “Probably.” He was leaning into Tony’s space.

“Need a hug?” Tony said, already lifting his arms to wrap them around Bucky’s shoulders. Both of Bucky’s arms came around his waist, pulling Tony firmly against him with a hint of desperation. Pressed this closely, Tony realized that Bucky was trembling. It was enough to break his heart. Out of everyone who did not need to deal with something like this right now, Bucky was at the top of the list.

“It’s just a lot,” Bucky whispered, the words meant for Tony’s ears alone.

“I know.” Tony hesitated. He couldn’t say that it would be okay, because he didn’t know that for sure, but… “You know we’re here for you, right? You don’t have to deal with this alone. Steve and I will be with you every step of the way. So will everyone else.”

Some of Bucky’s tension eased. “That’s the only reason I haven’t freaked out,” he replied.

Tony tightened his grip. “We’re gonna do everything we can, both for you and… and for her,” he said softly. “The best psychologists, the best doctors, the best lawyers… seriously, whatever you need.”

“You’re too goddamn good to me, Tony.” Bucky sighed, resting his head atop Tony’s.

“I wouldn’t go that far,” Tony said. He really should have found this information earlier. He didn’t know why he hadn’t expected Hydra to have more than one Winter Soldier. _Of course_ they would’ve created more: what evil group bent on world domination wouldn’t want a bunch of blank slate weapons under their control? Who knew how many lives he could’ve saved by figuring this out sooner?

“Hey,” Bucky said, pulling back to give Tony a cross look. “Stop that.”

“Stop what?” Tony said, pasting on an expression of innocence. Unfortunately, Bucky wasn’t fooled for a moment.

“You did plenty. More than anyone else did. You found her.” Bucky turned his head to look at the capsule, and more specifically at the woman inside. There was something deeply sad in his expression.

“Do you think she’s yours?” Tony asked before he could stop himself.

“Yeah, I do. Clint’s right. She looks like me. Like me when I was younger in those pictures that Steve has. You can do a paternity test, but… I’m pretty sure I know what it’s gonna say,” Bucky said.

“I’ll have one done as soon as we’re back to the tower,” Tony promised, to keep himself from asking what he really wanted to know. Truth be told, Bucky probably couldn’t say whether he’d ever wanted kids. Pre-Hydra, Bucky Barnes had been shipped off to a war zone. Post-Hydra, Bucky was just trying to get through each day without having a panic attack or a traumatic flashback. Kids probably hadn’t ever entered the mix as more than a passing thought or, at the most, a pipe dream.

As promised, as soon as they returned to the tower, Tony and Bruce took the capsule and their unconscious guest down to Tony’s workshop. Bruce deemed the capsule safe to open, so, with Clint and Natasha on guard just in case, Tony did so to allow Bruce to take several vials of blood for testing. JARVIS was able to run the paternity test right there, since he had Bucky’s blood on file. The result was as they expected.

“I guess that’s it then,” Clint said with a low whistle when they heard.

Tony sighed. “This is so fucking unfair,” he said to no one in particular. “Why can’t Bucky catch a break?”

“Do you want me to tell them?” Natasha asked, looking at Tony.

“No. I think it should be me,” Tony said, running a hand through his hair. “Bruce, do you mind looking at the data JARVIS pulls up? I’m sure the next question is going to be when is it safe to wake her up.”

“How about never?” Clint said.

“Clint,” Bruce said, giving Clint a look.

“What? I’m just saying, if she’s anything like Bucky was… I don’t particularly want to have my ass kicked again by a Winter Soldier if I can avoid it,” Clint said, and honestly, no one could argue with that.

“I’ll review everything,” Bruce said finally. “I’m not sure it’ll tell us much about her state of her mind, though.”

“I’ll help,” Natasha volunteered.

Tony left them to it and walked out of the workshop only to find that Steve and Bucky were right outside. He drew to a stop and blinked at them, ignoring the familiar flutter in the pit of his stomach. These two were literally all Tony had ever wanted. For the past several weeks, they had been dancing around… something. Tony didn’t dare put a name to it yet, especially since he wasn’t sure anything would happen now that they had something way more important to focus on. 

Still. He ached a bit with the desire to be able to seek comfort in Steve’s arms, or kiss the worried frown away from Bucky’s face. They’d been _so_ close…

“Well?” Steve said when the silence had dragged on a bit too long.

“JARVIS verified it. She’s Bucky’s daughter,” Tony said quietly.

Steve grimaced. “And the mother?”

“Looks like a Hydra agent,” Tony said. “Deceased.”

“Shit,” Steve muttered. 

“I’d like to talk to her,” Bucky said.

Tony and Steve exchanged a look.

“What? What’s that look?” Bucky said, glancing between them.

“It’s nothing,” Tony said. “Look, Bruce, Natasha and Clint are reviewing everything we’ve got. So is JARVIS. We just want to make sure she’s safe to wake up. We don’t want her to attack anyone, and we don’t want to have to hurt her if she does.”

“When will you know?” Bucky asked.

“Soon,” Tony said, relieved when Bucky appeared to accept that. Bucky walked past, into the workshop, and Tony bit his lip as soon as the door slid shut.

“This is a disaster,” Steve said. “Bucky’s not in the right place for this.”

“I don’t disagree, but… Steve, really, is anyone ever in the right place for this?” Tony said.

Steve cracked a smile. “No, I suppose not. I just… I worry about him.”

“I know you do. I do too. But that’s why Bucky has all of us,” Tony pointed out. “So we can help him. I mean, if we weren’t here, either he never would’ve found out about her or he would’ve found out and had to deal with this alone. Neither scenario is ideal.”

“You’re right. Damn Hydra,” Steve said, shaking his head and sighing. Tony couldn’t help himself; he reached out, putting a hand on Steve’s arm. Steve looked up at him, then turned his arm over and shifted until he and Tony were holding hands. Tony laced their fingers together and squeezed, trying to figure out what the best thing to say would be.

And then Clint screamed his name.

Tony launched himself back through the doors, Steve at his heels, and came to such a sudden stop that Steve banged into him. The capsule was open. Natasha and Clint were standing in front of Bruce. Neither one of them had drawn their weapons yet, but Tony knew they were both armed. Bucky was standing a few feet away from them, looking like he didn’t know what to do.

The Soldier – Katrianne, Tony reminded himself – was standing in front of the capsule.

She blinked very slowly, eyes taking in the room, but made no move to attack. Her hands hung loosely at her sides. She was shorter than Tony had realized, even shorter than Natasha, probably somewhere around 5’4. Unlike Bucky, she wasn’t heavily muscled. All in all, she didn’t look very intimidating. But that was probably something that Hydra had done on purpose. They wouldn’t want people to realize that she was a threat until it was too late.

“JARVIS, what the fuck,” Tony said tensely.

“My apologies, Sir. It appears the capsule had a time release,” JARVIS replied.

Katrianne startled when JARVIS spoke, taking a step back. Her already wide eyes grew wider. All of them tensed. Steve stepped forward, pulling Tony behind him.

But she didn’t attack.

When it became clear that nothing was going to happen, Tony decided to speak up. “Hello. Do you know where you are?” he asked, figuring that it couldn’t hurt to ask.

She remained quiet for a moment before she spoke in lightly accented English. “No. Are you my new handler?”

Bucky flinched.

Shit. Tony considered the best response and finally said, “You don’t have a handler now. We took you away from Hydra.” He wanted to see how she would answer that. Back when Bucky was more Winter Soldier than human, he had been utterly baffled by the concept of not having a handler. Steve had often had to step in and act like a handler to keep Bucky from losing it.

Katrianne looked as confused by that statement as Bucky once had. “What are my orders?”

“Your orders are to stand right there until you’re told otherwise,” Tony told her. “JARVIS, get Dr. Laurie on the phone, would you?”

JARVIS knew enough not to answer, but the cell phone in Tony’s pocket began vibrating. Tony took it out and backed off, keeping his eyes on Katrianne. Dr. Laurie was Bucky’s psychiatrist, and she had been working miracles with him. If she couldn’t, or wasn’t willing, to work with Katrianne, then maybe she could suggest someone who would – and at the very least, it looked like Bucky was going to need some support. 

He had the feeling it was going to be a long night.


	3. Chapter 3

Failure was not an option. There had to be a way to fix this. Tony stood in the midst of several holograms, arms folded across his chest. In the three weeks since they had found Kat, he’d been optimistic that there would be a way to help her. The B.A.R.T. had helped Bucky so much that Tony had been sure… but two nights ago, when they hooked Kat up to it, it hadn’t done anything at all.

“She has no concept of positive memories, Dr. Stark,” Dr. Laurie had said gently. “Bucky was a different case. He had a life before he was captured by Hydra. Those memories still existed inside of him. Katrianne doesn’t have that luxury. It’s impossible to overwrite or modify negative memories when you don’t know how, or you don’t have anything to compare them to.”

Tony blew his breath out in a long sigh, hanging his head in frustration. If the B.A.R.T. didn’t work, he wasn’t sure where to go from here. Kat was similar to Bucky in that she had a Winter Soldier side – which, thankfully, did not seem violent – and a “normal” side. The “normal” side, such as it was, seemed more like a blank slate. And that was likely what had prompted Dr. Laurie to make the recommendation that she had.

Age play. He rolled the words around in his mind, mulling them over for what must have been easily the hundredth time. Tony was familiar with the concept, though he had never partaken in it directly. What Dr. Laurie had suggested was the strictly nonsexual variation of course, wherein Kat would get to act like a child and experience all the things that children did when growing up.

He wasn’t opposed. Not exactly. It was unique for sure, but in some ways, based off of his own observations about Kat’s behavior so far, the suggestion seemed to fit, and it made logical sense. But… there was just something about it that seemed kind of weird. Tony sighed and rubbed a hand over his face. They didn’t know how Kat would react to it, and Tony wasn’t sure if Bucky and Steve could do it. Both had looked perturbed when Dr. Laurie made her recommendation. Tony had already asked JARVIS to gather some research together that would help them better understand what age play.

“Age play is our best option right now. I believe it can help Katrianne develop her personality and learn to identify her wants and needs. But it will require a commitment on the part of you, Bucky and Steve. You will be her caregivers and she will look at you the way a child would her parents. Don’t start this process if you’re not sure that you can commit to it, because you’ll do her more damage in the end than she would right now. If you’re not comfortable with it, we can move to the next steps.”

Dr. Laurie’s words floated through his brain. The next step was some form of institutionalisation, Tony strongly suspected, though she hadn’t come right out and said that. The thought of Kat going to one of those places, no matter how well she would be treated, made him uncomfortable. They’d probably put her through a similar process there, but… she deserved better than that. 

A shuffle behind him was the only warning Tony got before hands landed on his shoulders. The familiar scent of Steve’s cologne followed a moment later. Tony sighed and relaxed into the touch as Steve started rubbing his shoulders, locating the tension knots with unerring accuracy. Sometimes he didn’t even notice how stiff he’d gotten until Steve’s magical hands started their work.

“You need to take better care of yourself,” Steve chided.

“Mm… why bother when I have you to do it for me?” Tony asked, letting his head roll forward again. He heard Bucky chuckle and glanced up to see that Bucky had taken a seat at Tony’s desk.

“He has a point, Stevie,” Bucky said, amused.

“Shut up,” Steve said, keeping the steady, wonderful pressure of his fingers up.

“You looked like you were thinking hard,” Bucky said, meeting Tony’s gaze.

“I was,” Tony said. He lifted his head a little and looked past Bucky. Yup, there she was. Kat was sitting on the spare couch that Tony had shoved into the corner of his workshop. Seeing her there, a blank expression on her face like a robot waiting to be started up, was hard. She wasn’t like a normal person; she didn’t run or laugh or tease. Hell, she barely smiled, like she wasn’t sure how. 

Maybe age play _was_ the answer, if she didn’t know how. Little things, simple things, childlike things, could those be the answer that Tony had been searching so hard for? He wondered if Kat would smile if he told JARVIS to start reflecting bright, pretty lights on the walls, or if she’d enjoy hearing the loud, enthusiastic music that usually appealed to children.

Steve followed Tony’s gaze and sighed. “You were thinking about what Dr. Laurie said.”

“Pretty much. Trying to figure out if there was any other answer,” Tony admitted, dismissing the holograms around them with a flick of his wrist. He could try amending the B.A.R.T., but how? You couldn’t use a machine to teach someone how to be happy. 

“We’ve been talking about it a lot,” Bucky said. “But we wanted to get your opinion before we decided anything.”

Tony shrugged, which sadly stalled the movement of Steve’s hands. “I don’t know. I think there’s merit in the idea. I’ve done some research and Dr. Laurie’s suggestion makes sense in a lot of ways… but it’s a big ask for you two.” Especially Bucky, who was, in many ways, still coping with what had happened to him. It might only be age play, and it wouldn’t be all the time, but a child was a big responsibility no matter which way you looked at it.

“For you too,” Steve said, and Tony startled.

“Me?”

“After us, you spend the most time with her. Sometimes even more than we do,” Bucky pointed out, which was the truth even if Tony hadn’t started out intending for that to be the case. It had just sort of… happened. Tony was quiet for a moment, enjoying the warmth and heaviness of Steve’s hands still on his shoulders, before he spoke.

“To me, it’s worth a shot. Maybe she won’t take to it. Maybe no one will be comfortable with it. But I think we owe it to her to try,” he said quietly. Tony’s childhood had been shitty, but at least he’d still gotten one. He could stand to play dolls or have tea parties, help her take a bath, or read her a story before bed. 

“That’s what we figured you would say,” Bucky said. There was something soft in his eyes that made Tony’s stomach twist; he was suddenly very aware of how close Steve was standing to him. His mouth went dry. He didn’t know whether to lean back into Steve or move forward towards Bucky, and the indecision left him aching.

Bucky made the decision for him, standing up with a slow, easy grace that Tony would never _not_ envy him for, and walked over to them. His footsteps were light, a holdover from the time as the Winter Soldier, and completely different from Steve, who tended to drag his feet when he walked unless Natasha was there telling him to pick up his feet. But Tony didn’t mind, because it made it easy for him to tell them apart.

“Bucky said you’d say yes because you bent over backwards to help him,” Steve said with a chuckle, his arms sliding around Tony’s waist. He rested his chin atop Tony’s head. Tony couldn’t help rolling his eyes. Yes, he was short compared to the two super soldiers. No, they didn’t have to do things like cuddle him just to remind him!

“It’s not a big deal. Just the right thing to do,” Tony said, a little embarrassed at the attention. They were acting like he’d done something special, but he hadn’t. 

“Sure,” Bucky said, taking Tony’s hands into his and intertwining their fingers. “That research you compiled for Stevie and me was really helpful, by the way. We weren’t even sure of what Dr. Laurie was asking until then.”

“Is it really a thing that people do?” Steve asked, curious, and Tony smiled.

“Yeah, it is. It’s not super popular, but there are plenty of people who find it comforting,” he said. Honestly, he could see the appeal in it himself. Being in control all the time was exhausting, so finding ways to let go was important. Tony was fortunate in that he had the Avengers, Rhodey, Pepper and being Iron Man to help, but not everyone was so lucky. And at the end of the day, if someone found a method of coping with life that didn’t hurt anyone else, what difference did it make?

“Have you ever done it?” Bucky asked.

Tony chuckled. “Ah, so that’s why you really came down here,” he teased. “I’m afraid that’s one thing that I don’t have any firsthand experience in, sorry. Besides, even if I did, it wouldn’t necessarily be the same. I don’t think you can tell what age headspace someone will have before you try.”

Bucky opened his mouth, but whatever he was going to say was never voiced as the sound of a soft giggle made them all freeze. As one, their heads swivelled around to locate the source. Unnoticed by any of them, Kat had moved from the couch to the ground – probably motivated out of curiosity for Dummy, who, equally curious, had rolled over to see the new human in his space. 

Evidently the two of them had come to some sort of agreement, because Dummy had fetched one of his favorite toys: a red foam ball that was easy for his claw to grab and hold. Tony had spent countless hours tossing that ball against the wall and letting Dummy retrieve it. Now, he, Bucky and Steve watched in dumbfounded silence as Dummy took the ball and rolled it across the floor to Kat. She grabbed it and held it up, looking at it like she had never seen something like it before, then rolled it back.

This game continued for at least two or three minutes before Steve found his voice and whispered, as though afraid to speak too loudly, “Are they… are they _playing_?!”

“I… I think so?” Tony said, blinking. 

“Did you tell Dummy to do that?” Steve said.

Tony carefully shook his head, not wanting to dislodge Steve. “No… but he and I play ball all the time… well, you guys know. You play with him too.” Steve was actually the one who had started playing this very game with Dummy, much to Dummy’s unending delight. Bucky preferred the game where he hid the ball in various places around the room and then Dummy had to find it.

Bucky had remained quiet up until that point, just watching. Finally, he said softly, “She looks like a kid.”

The statement made Tony take a second look at the scene, and he realized that Bucky was right. That was definitely a childlike innocence and wonder shining in Kat’s eyes as Dummy rolled the ball back to her. The roll went wild, bypassing Kat by a couple of feet – Dummy’s coordination wasn’t the best. But Kat didn’t get mad. Instead, she got to her feet and went after the ball with the same dogged determination Bucky displayed when he found out that Natasha was baking.

Kat reached the ball and bent down to pick it up. Holding it carefully, she walked back to where she’d been sitting previously and sat again. Then she rolled the ball back towards Dummy. The corners of Tony’s mouth quirked up in a smile as he watched Dummy open and close his claw, a sign that Dummy was very happy, before Dummy caught the ball and rolled it back.

“You know, this may be easier than I thought it would be,” Tony remarked. It was really nice to see Kat smiling: the smile softened her face, making her look younger. He was pretty sure that was one of the first _real_ smiles she had ever given, and all because a needy ‘bot had wanted to play.


	4. Chapter 4

**Notes for the Chapter:**

> The Very Hungry Caterpillar was written by Eric Carle. The lines taken from the book don't belong to me.

“He built himself a small house, called a cocoon, around himself. He stayed inside for more than two weeks,” Tony read. He couldn’t help glancing away from the page to sneak a look at Kat’s face, and his lips quirked up into a smile when he saw how utterly enthralled she looked.

It had been two weeks since they decided to go ahead with the age play idea. There had been a bumpy moment or two, but for the most part Kat had taken to age play like a duck to water. She’d only had one day so far where she’d got up and decided she didn’t want to play, which was fine: they had all agreed that it was important not to push her when she wasn’t feeling it.

After some trial and error, and with a laughing Clint’s help, they had finally worked out a routine for her. Bucky spent the most time with her by far, since he was the only one out of he, Tony and Steve who didn’t have a job. Tony did what he could; he knew Pepper and Rhodey thought that having Kat around was just amazing, because it meant Tony limited the hours he was spending in the workshop instead of staying down there for a week straight.

He was always the one who put Kat to bed, though. After watching television curled up under Steve’s arm, she’d shuffle sleepily down the hall and climb into her bed. Tony would come sit beside her with a couple of books that varied in age ranges and he would read to her. He usually started with a book meant for older kids, reading a chapter or two out of that, before switching to a book meant for much younger kids which were easier to understand – he’d noticed Kat got frustrated quickly when she couldn’t fully understand something, and that happened a lot when she got sleepy and her grasp on the English language loosened.

That was happening now. Kat’s small hand grasped his arm, and she said sleepily, “What’s a cocoon?”

“Umm… a cocoon is like a ball of silk,” Tony said. That wasn’t exactly right, but it was the simplest comparison he could think of. “A caterpillar can produce silk and wrap it all around himself. Like this, see?” He pointed to the picture, which looked more like a brown pinecone than anything.

Kat traced the outer edges of the cocoon. “Like la chambre?” she asked solemnly, and Tony was hard-pressed to hide a wince.

“No, honey. Not like la chambre at all,” he said quietly. ‘La chambre’ was what Kat called the cryostasis capsule. It gave Tony chills to hear the unnaturally blank way she always said it, a reminder that she could be one or two words away from becoming a mindless killer.

They didn’t know if Kat had code words implanted in her mind. Bruce, Natasha and Bucky all thought it was likely that she did, though of course those words would be French in origin as opposed to Russian. If she did, they had no way of knowing what those words might be. Dr. Laurie was optimistic that, given a few months of age play, that Tony would be able to try again with B.A.R.T. – and if it worked, and she did have code words, they’d be able to free her just like Bucky.

Kat scrunched her nose up. “I don’t understand.”

“It’s like… a cocoon is a good thing. The caterpillar built it himself, see?” He ran a finger beneath the corresponding words on the page. “Because he wants to change.”

“Oh. Okay,” Kat said, even though he was pretty sure she didn’t fully understand. Much like a child, much like Bucky when he’d first come to the tower, some concepts were very hard for her to grasp. 

But it was working. Tony could see it. She was developing a personality. She reacted to things now. She asked questions, even if it was only to specific people. She smiled. More rarely, she’d laugh. There was still a long way to go, though. Again, like Bucky when he’d first come to the tower, she had very few opinions. Whatever she was given was good enough. It drove Steve crazy. He was constantly trying to get her to pick one thing or the other, until finally Bucky would gently intervene.

Tony figured – hope – that would come in time, like it had for Bucky. They all had to be patient. Dr. Laurie had already confirmed that Kat was making good progress… but that what they had to keep in mind was that progress looked different for everyone, and that Kat wasn’t Bucky. In some areas she might progress faster, but in other ways she would progress slower or not at all.

“Where were we?” Tony murmured, looking back at the page. “Oh, right. Okay. ‘Then he nibbled a small hole in the cocoon, pushed his way out, and…’”

“He got out?” Kat asked.

“What?”

She looked up at him and, in that infamously blunt way of children, said, “He got out on his own. He wasn’t strapped down? They didn’t have to let him out?”

Shit. Tony exhaled, trying not to react in any other way. “No. Because he built the cocoon himself, remember? No one put him into it.”

Kat frowned but said nothing else, obviously chewing that over. Tony forced a smile and turned the page.

“Then he turned into a beautiful butterfly,” he said, looking down at the brightly colored image. He was beginning to think that reading this book had been a mistake. He had chosen it because he remembered loving it as a little kid; Jarvis had been a great storyteller. But he hadn’t stopped to think about the potential comparisons that someone like Kat might draw.

From now on, he reflected, he was going to give Bucky all of the books he planned to read to Kat and have Bucky look them over first. Bucky wouldn’t have the exact same triggers as Kat, of course, but their experiences had been similar enough that Bucky could at least vet the worst of the books. The whole point of this was to give Kat good memories and experiences, not remind her of the worst of what she’d been through.

“Un papillon,” Kat said, touching the page. She was smiling now, which eased some of Tony’s anxiety.

“That’s right,” he said. “Maybe tomorrow you can paint with Cap, and he’ll show you how to make your own papillon. Would you like that?”

Kat’s eyes lit up. “Paint with Cap! I want to!” She started to get up.

“Whoa! I said tomorrow, kiddo, not now. It’s bedtime,” Tony said with a surprised chuckle. 

“Tomorrow?” she repeated, looking disappointed as she laid back down.

“Yeah, tomorrow.” He stood up, setting the books aside, and pulled the covers up around her shoulders. She knew the routine: she closed her eyes obediently and settled back into her pillow. 

“Good night, Tony,” she said.

“Good night, Kat,” Tony whispered. He was the only one she called by name. Steve was always ‘Cap’ and Bucky was always ‘Winter’. The nickname had bothered Bucky a little at first, but he’d become used to it surprisingly quickly and had never pressed Kat to call him something differently.

He tiptoed towards the door – useless, because Kat’s hearing was almost as good as Steve’s or Bucky’s, but he felt like it was something he should do – and, after switching on the nightlight, turned off the overhead light and slipped out. He shut the door behind him and sighed, lightly bumping his forehead against the door. One step forward and six steps back, that about covered it.

“Great job, Stark,” he muttered to himself, turning away. “J, monitor her, would you?”

“Of course, Sir.”

Tony headed down to his workshop; he was working on the newest upgrade for the tablet that was on the market, and Pepper wanted it done as soon as possible since Apple had just launched the new iPad. He was planning on some rudimentary holographic upgrades. Nothing fancy, certainly legions below what was available in the tower never mind in his personal workshop, but more than enough to blow the iPad out of the water. 

He whistled softly to himself as he sat at his desk and got to work. Though he had people who could do some of the work for him, Tony preferred to go over the tiny details himself. Never again was he going to be so detached from his company and what they sold that someone would be able to weasel through the cracks like Obadiah Stane had. That was a promise Tony had made a long time ago and which he intended to keep.

Some time passed. Tony couldn’t be sure how much. Later, when Bucky asked, he thought he’d put Kat to bed around 9:30pm, and it was after midnight when JARVIS spoke up. In the end, Tony supposed that it didn’t really matter how long she had been asleep for before the nightmares hit. JARVIS alerted him as to what was happening and Tony was out of the workshop like a shot.

“Damn, damn, damn,” he hissed. “JARVIS, ban all copies of _The Very Hungry Caterpillar_ from the tower, okay?”

The elevator doors slid open before JARVIS could respond. Tony rushed out, realizing that the door to Kat’s room was open. Bucky was in there already, sitting on the bed beside Kat and giving her a hug. Kat sniffled and Tony stopped, stunned. In all her time here, he had never seen Kat cry or show any other negative emotion aside from anger or frustration. But right now, there were tears running down her cheeks. The sight was so unexpected that for a moment, Tony had no idea what to do.

Then Bucky looked up at him and said to Kat, “See? Tony’s here. He wouldn’t be here if you were back with Hydra.”

Back with Hydra. Of course. Tony forced himself to calm down and approached the bed. “Bucky’s right. You’re in the tower, Kitty Kat,” he said as soothingly as he could.

“Just a dream,” Kat said, looking up at him so fearfully that it almost broke Tony’s heart. Just as bad, maybe even worse, was the echo of terror in Bucky’s eyes. How many nights had first Steve, and then Tony, stayed awake with Bucky because Bucky was convinced that Hydra was going to come back for him? 

“It’s not a dream. You’re here. Bucky’s here,” Tony told her, taking a seat on the opposite side of the bed. He wrapped his fingers around hers, realizing how cold her hand was.

Kat shook her head. Her hair was matted to her forehead with sweat. “Ils viennent!” she cried.

Bucky, who wasn’t that familiar with French, glanced at Tony. “What does that mean?”

Tony sighed. “They’re coming,” he answered quietly, mind racing. There had been one thing that had helped Bucky… just one… He took out his phone. He knew that Steve was at SHIELD tonight, doing some kind of nightly training class for the new recruits, but this was more important.

Roughly thirty minutes later, the door opened again, and Captain America walked in. He was fully suited up and clutching his shield. He stopped, struck a pose, and announced, “Fear not, for Captain America, the enemy of Hydra, is here to protect you!”

There was a pause, and then Kat looked up with shiny eyes. “Cap?” she whispered.

“That’s right. Cap came to protect you,” Tony said, wrapping an arm around Kat’s shoulders.

“I’m going to stand guard all night,” Steve said, assuming a position in front of the door. “No one will be able to get to you, right Buck?”

Bucky’s mouth had fallen open when Steve walked in. A hard nudge from Tony was enough to snap him out of his stupor, and Bucky quickly nodded. “Right. Cap can take any of those Hydra idiots with his eyes shut. You got nothing to worry about so long as he’s here.”

“And now you know it’s not a dream, because you could never dream up something that cool,” Tony told her, hoping to coax a smile out of her. Though she sniffed and wiped at her eyes, she didn’t smile. But she also didn’t start crying again, so Tony considered that to be a win.


	5. Chapter 5

“Look!”

“Just a moment, sweetheart,” Tony said, frowning fiercely at his tablet. He _knew_ he had seen a clause in here that addressed a significant issue – but damned if he could find it.

“Tony, look!” The exclamation was accompanied by a piece of paper that was shoved under his nose without preamble. Tony blinked and pulled back slightly, realizing that it was a drawing of the Avengers. Or at least, he assumed that’s what it was. The stick figures left a lot to the imagination – Bucky was already joking that Kat hadn’t inherited Steve’s talent for drawing.

“It’s beautiful,” Tony said, recovering quickly and setting his tablet aside. “Why don’t you tell me about it?”

Kat’s frown was instantly wiped away by a look of fierce concentration. “Iron Man,” she said, pointing to the red stick figure. “Hulk. Hawk.” She pointed to a green and purple stick figure respectively. 

“Very nice. How come you didn’t add Cap, Winter or Black Widow?” Tony asked.

“They’re on a mission,” Kat said, as though that were perfectly obvious, and she couldn’t fathom why Tony wasn’t smart enough to get that on his own. Recognizing himself in that tone, Tony privately reflected that he and Kat might be spending a bit _too_ much time together. 

But that was the problem when you were around a kid, or even someone who was age playing. You never knew what they were going to pick up from you. It just meant that Tony would have to be a little more careful when he was talking on the phone and Kat was in the room, that was all. Though he had to admit, it was a little flattering that she was picking things up from him.

He’d noticed that more and more lately – Kat had begun drawing like Steve, she’d taken to watching the same shows that Bucky did, and she was copying Tony’s way of talking and standing. Dr. Laurie had been very amused when Tony mentioned it to her and had reassured him that it was normal for children to mimic their parents. According to her, it was a sign that Kat was developing more of a personality.

“Well, why don’t you draw a picture of them on the mission?” Tony suggested.

“No,” Kat said decisively, and Tony blinked at her in shock.

“No?” he repeated, slightly disbelieving that that word had just come out of Kat’s mouth. For a while there, he hadn’t even been sure if she knew the meaning of that word. Bucky sure hadn’t. It had taken Bucky close to six months to be comfortable making a decision between two things, never mind outright saying no.

But Kat gave her head a stubborn shake and said, “I want to draw Iron Man rescuing puppies.”

“I… would love to see that,” Tony said, recovering quickly. As Kat turned back to the coffee table, where she’d been kneeling on the floor and coloring, he whipped out his phone and quickly texted Steve, Bucky and Dr. Laurie in that order. Dr. Laurie would need to know about Kat’s progress, but more important Tony, Steve and Bucky would need to know how to handle this if the word “no” was going to start becoming a regular part of Kat’s vocabulary.

They hadn’t even really talked about punishments, Tony realized as he watched Kat bend her head to her drawing. They hadn’t needed to. Much like her father had been, Kat was extraordinarily obedient. She did what she was told when she was told, and – up until now, anyway – she did it without a word of compliant. It was one of the reasons that getting her set up on a routine in the beginning had been so important, because otherwise Tony, Bucky and Steve were often left at a loss as to what to do with her.

They had a good routine now: Kat got up around 9am. Bucky fed her breakfast and then took her down to the gym for some exercise. Then she would go down for a nap. Steve would get her up for lunch, and then he usually took Kat out – to the park or for ice cream or even just to see New York; she felt most comfortable outside the mansion with ‘Cap’. She now joined the whole team for supper, and then after that Tony got the chance to play with her before bath time and bed.

But it was still hard to get Kat to make choices. When presented with an option between strawberry or chocolate ice cream, Kat would remain quiet, occasionally shrugging, until someone else made the choice for her. She was still very much like that; Tony didn’t know how they were going to break her of that. He had actually expected her to start making choices before she started saying ‘no’, but of course – he smiled ruefully to himself – she was subverting his expectations as always.

Dr. Laurie had told them that making choices was something that would come in time; she had also pointed out, with a smile that meant she was trying not to laugh, that some people just didn’t care very much about ice cream flavors. The indignant look on Steve’s face when he heard that was a memory that would forever leave Tony amused: Steve cared _very_ much about ice cream.

Perhaps, Tony thought, they just weren’t offering Kat the right _kind_ of choices. He slid off the couch and sat beside her, watching her draw for a little while. He supposed that when you came from the kind of background that she did, ice cream flavors didn’t matter much. Kat had never had ice cream before coming to the tower. So why would the flavor matter, when in the end she was still getting such an amazing treat?

But something like how she spent her time – that might matter more. Tony cleared his throat. “Hey Kitty Kat, I know Bucky and Steve are busy today,” he began. The two of them, plus Natasha, really were on a mission. “But what would you think –”

The Avengers alarm began to blare, accompanied by the flashing lights that told Clint something was up when Clint didn’t have his hearing aids in, before Tony could finish his sentence; he jumped and Kat whimpered, hunching in on herself. Shit. Tony reached out automatically, wrapping an arm around her shoulders as JARVIS cut the alarm. The sudden silence was overwhelming, broken only by the sounds of Kat gasping.

“Sir, there is a problem. The Captain is requesting your presence immediately,” JARVIS said, and then he gave an address that Tony didn’t recognize, but which was right here in New York.

“Right,” Tony said, an artificial calm settling over him. Bucky and Steve knew that he was home with Kat, so if Steve was calling for Iron Man then things must be pretty damn dire. He didn’t have much time to waste. 

But there was also Kat to think about. Since she’d come to the tower, Steve, Bucky and Tony had made it a point to divide up their time so that she was never without one of them. Dr. Laurie had told them at Kat’s last session that it might be time to think about leaving her alone with someone they trusted and who Kat got along well with; she had suggested Clint, because Clint had experience with little kids.

Unfortunately, Tony was pretty sure that the other Avengers were on their way to whatever was going on. Calling one of them and asking them to come back to the tower to look after Kat wouldn’t be fair, but Tony couldn’t exactly leave Kat alone. She may have looked like an adult, but mentally her headspace was much closer to four or five. But Steve…

Tony made a decision. “JARVIS, call Pepper and tell her I need her to come get to the tower immediately,” he ordered. If he remembered correctly, Pepper was attending a meeting uptown. It should only take her about ten minutes to get to the tower.

“Calling, Sir,” JARVIS said.

“Kat, I have to go,” Tony said, turning to Kat. She watched him with wide eyes. “I’m going to take you down to my workshop. You can stay with Dummy and JARVIS until Pepper comes, okay?”

“Okay,” Kat whispered, even though she clearly didn’t want him to leave. The scared look on her face broke Tony’s heart, but he didn’t have a choice in the matter. As they hurried down to the workshop, he told himself that she would be fine. The tower was arguably the safest place in New York, and Tony’s workshop was the most secure spot in the whole tower. Plus JARVIS would be watching over her, and JARVIS would never let anything happen.

He made sure Kat was secure in the workshop, gave her a hug goodbye, and rushed back into the hall. As the elevator doors closed behind him, he hoped that he wasn’t making a mistake. Why hadn’t they put more thought into this possibility? They should’ve made more contingency plans… they should’ve lined up a trustworthy baby-sitter… they should’ve _thought_ about this…

“We’re the worst parents ever,” Tony muttered. The elevator doors opened and he rushed out, heading for the nearest window. He tapped the arc reactor twice as he leaped out the window; the nanobots formed the armor before he had even started to really fall. The thrusters engaged and Iron Man shot towards downtown New York.

“Pinpointing the address Captain Rogers gave,” JARVIS said.

“Thanks,” Tony said absently. Information flashed across the HUD at an advanced rate. Bucky had once complained, when he tried the helmet on for fun, that he didn’t know how Tony did it, because all the data that Tony had to absorb all at once was dizzying. Tony disagreed. True, it had taken him a little time to get used to the armor – but now he loved it. Having so much information available at his fingertips was incredible. 

He made quick time towards the address that Steve had given, but all was quiet when he got there. Tony touched down, the boots making a heavy metallic sound as they hit the concrete and looked around. His heart thudded against his ribs. Something wasn’t right, clearly. It was possible that the fight had gone somewhere else, but honestly it didn’t even look like a fight had taken place.

And then, to his left, the air shimmered. That was all the warning Tony got before beams of brightly colored light started flying in his direction. He somehow managed to dodge all of them, ending up about twenty feet from where he’d first started. The ground in between was literally melting. His stomach clenched as he realized what could’ve happened if one of those beams had hit him, and he looked up.

“Iron Man, we’ve been waiting for you.” The speaker was a figure dressed entirely in black. Even their face was covered in black fabric, with no holes for eyes or lips. There were six of them total, each indistinguishable from the other. Tony couldn’t even tell if he was dealing with men or women.

“What the hell is this?” Tony asked, fighting to keep his voice even. 

“A billion dollars.”

“What?” Tony said.

“A billion dollars for their lives of your friends.” The air shimmered again, to his right. Tony tensed, but no more beams of light came. Instead, as though by magic, Steve, Bucky and Natasha appeared. They were bound and gagged and guarded by another half dozen black figures; three of them held guns to the heads of the Avengers.

“I don’t have a billion dollars available to me right now,” Tony said tightly. It was a common misconception, but one that he hoped wasn’t about to cost him the lives of his teammates.

“Then you’ll have to –”

There was the sound of five gun shots in rapid succession; the three figures holding guns to Natasha, Steve and Bucky collapsed. So did the one who had been speaking to Tony and another one just beside. Tony blinked in astonishment; his first thought was Clint had arrived on scene, but those had definitely been gun shots and not arrows –

A blur descended on the remaining two figures guarding Bucky, Steve and Natasha. Tony watched, shocked, as the two figures had their necks snapped. The bodies hit the ground as the blur straightened up and turned around. His jaw dropped as he took in the uniform – one of Natasha’s Black Widow uniforms, if he wasn’t mistaken – and the weapons – Bucky’s – and face.

It was Kat.


	6. Chapter 6

“JARVIS, what is she doing here?” Tony hissed, his heart thudding at the sight of her. 

“I apologize, Sir. I tried to keep her in the tower, but she circumvented my protocols,” JARVIS said. “She got out past Ms. Potts.”

“A little heads up would’ve been nice,” Tony said tightly. Kat didn’t _look_ like she’d lost control, but that didn’t always mean a whole lot. Her eyes were calm and focused, even though she had just killed seven people. Then again, she had killed far more people in the past under Hydra’s direction…

“My apologies, Sir. I was trying to assist Ms. Potts in finding her. I was unaware that she was coming here,” JARVIS said. “She doesn’t have a communicator.”

It probably wouldn’t have mattered even if Kat had been wearing one. Tony didn’t think they were dealing with the cute little girl who giggled and clapped her hands whenever Bruce purposely let his skin turn green to entertain her. But he couldn’t tell if this was Kat’s older headspace, her normal adult self, or Printemps, the Soldier that Hydra had turned her into. Or even something in between?

“Kill her!” one the figures shouted, the moment of shock over, and Kat leaped into action. 

She was astonishingly fast, possibly surpassing even Bucky or Steve: which made sense, Tony reflected, because she definitely wasn’t as strong as those two, but she was much smaller and lighter. Perhaps Hydra hadn’t seen the need for another inhumanely strong Soldier but had instead focused on someone who was capable of blink-and-you-miss-it kinds of speed. That was dangerous in its own way – which Kat was proving right now.

In the span of about two minutes, the fight was over.

Tony stared at the bodies on the ground in mute astonishment as Kat carelessly pulled one of her knives free of a body and used it to cut Natasha, Steve and Bucky free. Bucky immediately stood up, taking a protective stance over Steve and Natasha, though he didn’t attack Kat. Tony wasn’t sure that Bucky could. Hell, he didn’t know if he could. This was Kat they were talking about…

But then Kat smiled brightly and said, “All gone!”

Bucky blinked. “Kat?”

“Bad guys all gone,” Kat said in her childish voice, her smile widening. “Can we go play now?”

“Uh,” Bucky said intelligently.

Steve stood up and gently helped Natasha to her feet. Tony was momentarily distracted by the sight of Natasha wincing and strongly favoring her left side; he did a quick scan with the armor and realized that she had broken at least two ribs in the scuffle – and if Natasha was openly showing pain, then it had to hurt a hell of a lot and she needed medical attention sooner rather than later.

He let the helmet slide back, though he didn’t remove the whole armor just yet, and said, “Kat, what are you doing here? I told you to wait back at the tower with Pepper.”

“I came to help,” Kat said simply, like Tony should’ve already known the answer to that. 

“So no one triggered you,” Tony said.

Kat cocked her head. “Triggered?”

“No one spoke French to you,” he amended.

“You do sometimes,” Kat said hesitantly. 

Tony glanced at Steve and Bucky. He wasn’t sure what they thought, but he didn’t think that they were dealing with the Soldier right now. Rather, he was pretty sure this was just Kat, out of her headspace and – and what? Dealing with a threat to the people that were taking care of her? Was that something Kat would even do? Would she make that decision on her own? He remembered his earlier thoughts that Kat wasn’t making choices because they didn’t matter to her, but that she might make a choice about how she spent her time if it did.

Had she made that choice?

“Okay, you two take Kat back to the tower. I’ll get Natasha to medical and then we’ll follow,” Tony said, making a quick decision when he saw Natasha wince again. “C’mere, Nat.”

“This is the one and only time I’ll let you carry me this way,” Natasha said grumpily as Tony very carefully picked her up. “And if you make any comments or quips about damsels in distress, I _will_ figure out a way to stab you through that suit.”

“I didn’t say anything,” Tony said innocently, activating the thrusters. He slowly flew Natasha back towards the road. JARVIS was telling him that SHIELD was there, which was good because they’d need someone to take care of the bodies. He mentally grimaced, already thinking about how they were going to spin this to the press. It never looked good when someone died on a mission.

More than likely, they’d have to release the details about Natasha, Bucky and Steve being taken hostage. Then they’d have to decide whether they wanted to tell the world about Kat, or if they wanted to pin the blame on someone else. He was pretty sure the decision would be unanimous about that. Guns and broken necks were more Natasha’s and Bucky’s style than anyone else’s. Tony hated the thought of them stepping up, but it was highly unlikely anyone would believe Iron Man had done that. 

He stewed over that as a SHIELD paramedic checked Natasha out. They agreed with Tony’s assessment of two broken ribs on her left side and bruised a few more. Unlikely that Natasha would be able to kill so many in that state. So Bucky, then. The idea sat uneasily in the pit of Tony’s belly. He hated that some people would automatically jump to the conclusion that the Winter Soldier had taken ever.

“Would you stop?” Natasha said as the paramedic stepped away, and Tony looked at her.

“What?” he asked blankly. 

“You’re overthinking things and I can hear it from here.” She stood and gingerly zipped up her uniform, hiding the bandages that had been wrapped around her midsection. “You’re worried about what to tell the press, aren’t you? You always get the same look on your face when that happens.”

“Yeah.” Tony sighed. He couldn’t even accuse Natasha of reading his mind this time, considering that that it was the obvious thing to be concerned about.

“It’ll be fine. Casualties happen on missions; sometimes it’s unavoidable no matter what we do. And if people start throwing a fuss, I’m willing to play up my injuries and pretend that they were hurting me,” she said.

“I thought you hated being seen as a damsel?”

“I do, but to protect Kat it would be worth it.”

“You’re such a softie at heart,” Tony teased, and she snorted and punched his arm.

“Please. You do know why she came here, right?” Natasha said.

“Ummm…” Tony said. “Of course I do, but if you’re willing to share your opinion, I’m happy to hear it.”

Natasha rolled her eyes. “Right. Kat is a trained assassin, Tony. I know you, Bucky and Steve all look at her like she’s your precious little girl, and that’s a good thing because it’s exactly what she needs… but that doesn’t erase the fact that she’s had years of being a Soldier. And if Hydra kept her around, she was damn good at it.”

“I’m not following,” Tony said, eyebrows furrowed.

“She was _protecting_ you,” Natasha said, faintly exasperated. “You guys gave her a home. You care for her. You’re her _parents_. Of course she’s going to do whatever she can to protect that.”

Tony just stared at her. Natasha sighed and glanced around to make sure that no one was close enough to overhear, then leaned in closer to him.

“When Coulson and Clint brought me in for the first time, I had never experienced anything like kindness before. It was intoxicating. I didn’t know people could be like that. It took me months to trust them, but once I did? You better believe I would’ve killed anyone who looked at them wrong. They were everything to me. Without them, my life had no meaning. Part of me was convinced I would end up back in the Red Room. I couldn’t let that happen. Coulson had to talk me down a few times, until I learned how to gauge the appropriate level of violence for a mission.”

“I didn’t know that,” Tony said, and she smiled thinly.

“It’s not a part of my past I’m particularly proud of,” she said quietly. “And I know it’s not exactly the same thing, because the Red Room never fried my brain the way that Hydra did… but I’m telling you, I know that’s why she showed up together. You, Bucky and Steve have to figure out some way to let her know that she doesn’t have to do that anymore.”

“That won’t be an easy sell since Bucky joins us in the field,” Tony muttered.

“No, probably not. But she’s a liability. She could fall into her headspace in the middle of a fight… or, if she’s got code words, someone could accidentally or, worse, purposefully activate them,” Natasha said. 

“I’ll have to talk to Steve and Bucky about it,” Tony said. “For now, come on. Let’s go home.” He reformed the helmet and gently picked Natasha up again. She slung her arm around the armor’s neck, perfectly comfortable in a way that most people weren’t as Tony activated the thrusters again. They shot up into the air above the city and he turned in the direction of the tower.

He contemplated Natasha’s words all the way back to the tower, realizing that she was more than likely correct. All Kat knew was that something was wrong, and Iron Man had disappeared to deal with it. Of course she had followed them. That was exactly what Bucky would’ve done, and in that respect Kat was too much like her father. The question was, how were they going to convince Kat that problems out in the field weren’t something she should be dealing with?

If it were Tony, nothing could’ve kept him away… nothing, he admitted to himself, except the possibility that he was putting everyone at _more_ risk by joining them. But he wasn’t sure Kat would understand that. After all, she’d taken out those twelve idiots today while Tony just stood there. And it didn’t seem fair to scare her with thoughts of the code words, especially since they weren’t completely sure she had them.

He landed on the balcony and set Natasha down. She headed straight for the elevator, and Tony knew that within the next five minutes she would be in a hot bath. He followed a moment later but headed for the floor where he knew that Steve, Bucky and Kat would be. It was important that they get this dealt with sooner rather than later, no matter how much he would’ve preferred putting it off.

When the elevator doors opened on Steve and Bucky yelling at each other, he kind of wished he’d just gone ahead and joined Natasha in that bath.

“What is going on here?!” Tony demanded, putting his hands on his hips.

“Steve yelled at Kat,” Bucky said, glaring at Steve.

“I didn’t yell at her,” Steve objected. “I raised my voice while telling her that she did something wrong.”

“She started crying!”

“Kids cry, Bucky! It’s what they do!”

“She’s fragile! We should’ve just let it go!”

“She needed to know that what she was doing was wrong!”

“Okay, both of you shut up right now!” Tony said loudly, pinching the bridge of his nose. Both of them stared at him, startled, and he added, “You’re both right. Steve, you shouldn’t have yelled. But Bucky, we absolutely cannot let this go. We need to talk to Kat about this, without raising our voices, but in a firm way that means she knows what she did today wasn’t something she can do again.”

He held up a hand when they both went to argue. “I don’t want to hear it. If you can’t behave, then let me know now and I’ll go talk to Kat myself. Alone.”

“… Fine,” Bucky mumbled, and Steve nodded.

“Good,” Tony said, wondering exactly when he had become the shining example of parenthood here. Howard must have been rolling over in his grave.


	7. Chapter 7

Kat was, as Tony expected, in her bedroom. He knocked lightly, then opened the door and poked his head in. She was curled up on her bed, knees pulled up against her chest, arms wrapped around her legs, still dressed in one of Natasha’s uniforms. She didn’t look up at him, but the tell-tale shaking of her shoulders spoke volumes. The sight of her simultaneously made Tony want to hug her and shake her at the same time.

“Hey,” Tony said cautiously, entering the room. 

“Bonjour,” Kat whispered.

“Technically, it’s ‘bonsoir’ since the sun is setting,” Tony said, aiming for playful. She sniffed in response and he sighed, taking a seat on the side of her bed. Bucky and Steve crowded into the room behind him, but neither of them seemed willng to approach the bed and instead stayed clustered near the door. Tony had to fight the urge to roll his eyes at them.

“I was just trying to help!” Kat burst out, lifting her head. Her eyes were bright with tears and her lower lip was trembling.

Tony sighed, realizing that – of course – Natasha had been right. He was quiet for a moment, looking at her face. In many ways, Kat was so terribly young. But in others, she was as old as Bucky. The dichotomy sometimes made it difficult to know how best to respond to her. But that was they had all signed up for, he reminded himself. They were lucky that Kat hadn’t done anything like this before, and now they had to react appropriately to keep from ruining everything they’d built.

“I know you were,” Tony said finally. “And we appreciate it. You saved Natasha, Bucky and Steve today.”

Behind them, Steve made a noise of protest. “Tony –”

Tony held up a hand to silence him, keeping his gaze on Kat. He felt that it was important to acknowledge the good in what Kat had done. How many times had Howard totally ignored Tony’s contributions, preferring instead to scold Tony or focus in on a tiny flaw? The situations weren’t identical, but they were close enough that Tony did not want to foster that sense of being ignored in Kat. 

She deserved to know that she really had helped today.The last thing they needed was Kat feeling like she had to prove herself in some way. Tony cringed at the mere idea, thinking carefully about how to phrase his next word. Kat had lit up at the praise, and he almost hated to bring her down, but…

“But Kat, you have to know that you are not allowed to go out into the field again unless you’re told otherwise,” Tony said, keeping his tone gentle but firm.

“But I helped!” Kat exclaimed, her face falling.

“You did, but in doing so you put yourself in a lot of danger,” Tony said.

“No I didn’t. I was fine!” she said.

“You were wearing a uniform that wasn’t yours, which means it wasn’t fitted to you, and working with weapons that you had never used before and so weren’t totally sure how they worked,” he pointed out. 

“It was a knife,” Kat said flatly.

“Tony made those,” Bucky spoke up. “When Tony makes something for us, they’re usually advanced. One of those knives has a special built-in compartment with poison in it. One press of a hidden button and the blade is coated in a very lethal poison that can kill in seconds. What if you had pressed that button and –” He couldn’t seem to bring himself to finish that sentence.

“Poison never killed me before,” said Kat, but with more uncertainty this time. Tony’s stomach clenched at that. She shouldn’t know that. And the way she said it – he tried not to think about Hydra purposely feeding her different kinds of poisons, and how scared she must have been as her body reacted in unpredictable ways. Bucky and Steve were capable of surviving different kinds of poisons and toxins too, but an incident six months ago had proven that it was a very painful experience.

He swallowed and said, “You never know when you’ll run into one that could.”

Kat was quiet for a moment, and Tony dared to think they’d got through with her, when her chin jutted out and she said, “Then you can make me weapons that don’t have poison in them.”

There was Steve’s stubbornness rearing its head. Tony shook his head. “That’s not the only issue. By going out in the field, you put _us_ in a lot of danger too,” he added when she went to protest. Kat’s mouth clicked shut and she stared at him in confusion. 

“What?” she said in a small voice.

“I didn’t know you were coming. No one did. I thought you were another enemy at first; I was ready to fire off a repulsor blast. What if I had hit you? I know you’re enhanced, but that still could’ve done serious damage to you.” He breathed shallowly at the thought. “There’s a reason we’re all in constant contact with each other. It’s so that we know where everyone is at all times.”

Kat frowned for a bit, then said, “So give me a communicator too.”

“No,” Bucky and Steve said in perfect unison. Kat pouted at them, looking exactly like Steve when he wasn’t getting his way. Tony tried to keep a straight face, clearing his throat.

“No,” he repeated. “That’s not happening. You’re not getting weapons or a communicator. Because the other part of this is that you’re just not ready for the field. You haven’t trained with the team. We don’t know what you are and aren’t capable of, and we haven’t devised _safe_ or _painless_ ways to figure that out yet. And there’s still a chance that, if you have the code words in your head, you could be turned against us.”

Her face fell. “So you’re worried I’m an enemy.”

Tony immediately said, “Not at all. I know you would never hurt us if you had the choice.” He reached out and put his hand on her hand. “We’re not saying no forever, Kitty Kat. In the future, if you want to fight with the Avengers like Bucky does, we’d be glad to have you. But those days are a long ways off, okay?”

“You’d really let me in the future?” she said doubtfully, looking past Tony at Steve and Bucky. Tony half-turned to see the two supersoldiers exchanging looks.

“If you got through all the tests and everything was okay, then we’d talk about it,” said Steve finally. Tony hid a smirk. He knew that Steve and Bucky would be doing everything they could in the future to steer Kat away from that path, just like he was sure that Kat would be digging her heels in and going for it with everything that she was.

Kat looked from Steve to Bucky to Tony, her eyes narrowed. “Really?”

“Yes, really,” Tony said, squeezing her hand. “Okay? No more trips into the field.”

“Okay,” Kat said after a significant pause, and Tony breathed a sigh of relief. 

“There’s the matter of punishment,” Steve said.

“Steve,” Bucky hissed as Kat stiffened.

Normally Tony would’ve agreed with Bucky and let the matter pass. But Dr. Laurie had already talked to them about this too. She had warned them that sooner or later Kat would start trying to push boundaries, and that they needed to discpline her when she did. Kat needed to know where the limits were, and more importantly she needed to know what would happen when she pushed those limits. She needed to know that they weren’t going to abuse her the way that Hydra had.

So Tony cleared his throat and said, “I’m afraid Steve is right. You won’t be getting any dessert tonight, and your bedtime will be an hour earlier than normal.”

He eyed Kat cautiously as he spoke, wondering how she was going to react. Howard’s punishments had always been slightly more… unusual. Some might go so far as to call them abusive. So Tony was basing this off of what Edwin Jarvis used to do when he was in charge of punishing Tony. Never cruel, never angry, just something small and simple that still had an impact.

“That’s it?” Kat asked.

Tony nodded. “That’s it.”

“But I get my dessert back tomorrow?” she pressed, and Tony had to smile.

“You get your dessert back tomorrow,” he confirmed. He was totally unprepared for Kat to suddenly throw herself at him, and was nearly knocked off the bed as a result. Bucky grabbed his shoulders at the last moment, steadying Tony as Kat broke down into sobs.

Tony shot a look of gratitude in Bucky’s direction even as he wrapped his arms around Kat and whispered to her, doing his best to calm her down. Nothing seemed to help until Steve and Bucky crowded onto the bed with them and wrapped their arms around both Tony and Kat. It warmed Tony’s heart to hear Steve apologize for yelling at Kat: he knew Steve’s reaction had been borne of fear, but it was still good for kat to hear it.

Eventually, Kat cried herself to sleep with her head on Bucky’s shoulder and both hands fisted in Tony’s shirt, her legs in Steve’s lap. Tony breathed a quiet sigh of relief. Time would tell how well the three of them had navigated this, and if Kat would keep her word about not going out in the field again, but he thought that everything had turned out, if not pretty well, then at least okay. 

“You did a great job, Tony,” Bucky said softly, and Tony’s head snapped up in surprise.

“What?” he said.

“Bucky’s right. You handled that masterfully,” Steve said. His eyes were so warm and full of pride. “I don’t know what the hell Bucky and I would’ve done if you weren’t here.”

“Probably made even more of a mess by arguing with each other when we should’ve been talking to Kat,” Bucky said with a rueful shake of the head. 

“You would’ve been fine. All new parents struggle,” Tony pointed out.

“You don’t seem to. It’s like you look at Kat and you know exactly what she needs and how to talk to her,” Steve said.

Tony flushed. “I don’t – I mean – ” Usually words were easy, but he found himself struggling to know what to say in the face of their unexpected praise. In a way, Kat was a combination of him, Bucky and Steve, but tempered by something that was uniquely Kat. It wasn’t always easy figuring out how he was supposed to react or relate to her, but Tony had never thought of it as being overly difficult.

“It’s okay. I’m just really glad that you’re here and that you’re helping us do this,” Bucky told him. “I’d be lost without the both of you. Thinking of trying to get along without you two makes my head spin.”

“Well, you’re never gonna have to worry. Tony and I are in it for the long run, right Tony?” Steve said.

“Of course. For as long as you want me here,” Tony said, and Bucky and Steve exchanged a look. Then they both smiled.

“How about forever?” Steve said, and, before Tony could do much more than blink, Steve leaned over and kissed him. As soon as Steve pulled away, Bucky was there. It was a little more awkward to kiss Bucky because Kat was between them, but Bucky managed. The back-to-back kisses left Tony’s heart fluttering.

“Forever,” he agreed breathlessly, and found himself smiling back.

**Author's Note:**

> Find me on [tumblr](https://tsuki-chibi.tumblr.com/).


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